Until now, the government has employed police and ideological militia to quell protests. But now Iran's Revolutionary Guard have vowed to weigh in. It ordered protesters to "end the sabotage and rioting activities" and warned them to be ready for a "revolutionary confrontation with the Guards, Basij, and other security ... and disciplinary forces" if they dared to gather in public again.

The Revolutionary Guard is tasked with preserving the 1979 revolution, The force was created by Ayatollah Ruhollah Khomeini because he did not trust the regular Army. The Guard is considered more ideological than the regular Iranian Army.

But on Monday afternoon an estimated 1,000 protesters tried to gather at Haft-e Tir Square in central Tehran. Row upon row of waiting riot police and militiamen kept them from assembling. They were met with teargas and bullets fired into the air. Throughout Monday night, Iranian state television reported that police had "prevented" further demonstrations, and showed footage of violence from previous days that included protesters beating up a basiji militiaman.The protestors had attempted to gather to remember a young woman killed during fierce clashes on Saturday that left at least 13 dead, by official count [Editor's note: Story updated to reflect what happened during Monday's protests.].

The student rembembered, Neda Agha Soltan, was reportedly shot in the chest by a basiji militiaman passing on a motorcycle. Graphic Internet video of the aftermath has turned her into an instant icon of the movement lead by defeated moderate Mir Hossein Mousavi.

A Facebook page titled "Angel of Iran" has been created to honor her. Authorities forbade a memorial service on Sunday. Mr. Mousavi – who has not been seen since Thursday – urged his followers late Sunday to keep up the pressure.

"The revolution is your legacy," Mousavi said on his website. "To protest against lies and fraud is your right. Be hopeful that you will get your right and do not allow others who want to provoke your anger ... to prevail."

The protesters who have choked the streets by the hundreds of thousands in the past week are calling for a rerun of the disputed reelection of hard-line President Mahmoud Ahmadinejad.

But the protesters are torn between their desire to challenge an election result they consider a fraud – relying on Article 27 in Iran's Constitution that says peaceful marches "may freely be held" – and their fear of more violent confrontations that won't bring them any closer to their goals.

"I'm feeling that it's something between them [rival clerics within the establishment], and we shouldn't get killed for it," says one protester, who asked not to be named for fear of reprisal. "I am wondering ... what can come of it? What are we going to get out of this?"

Iranian officials announced that 457 people had been arrested on Saturday, and five members of the family of former President Hashemi Rafsanjani – including his politically active daughter – had been arrested and released.

"Giving up hope is probably the worst thing we could do [but] you just don't know what these people are going to do and what they are capable of," he says in a phone interview. "We're not violent, but they can be."

Just a little fraud?

A spokesman for the Guardian Council – a hard-line body of 12 clerics that is loyal to Iran's supreme religious leader, Ayatollah Sayed Ali Khamenei, and supports President Ahmadinejad – said complaints of fraud were overblown.

"Statistics provided by the candidates, who claim more than 100 percent of those eligible have cast their ballot in [between] 80 [and] 170 cities are not accurate," Abbas Ali Kadkhodaei told state TV. "The incident has happened in only 50 cities."

While Mr. Kadkhodaei said that problem could affect 3 million votes – in a race in which Ahmadinejad officially won 24 million to Mousavi's 13 million, he said it has "yet to be determined" if it would adjust the result.

But Ayatollah Khamenei ruled out any change in the result during a sermon last Friday. A foreign ministry spokesman called the June 12 vote a "brilliant gem shining on the peak of the Iranian election," and accused Western nations and the media of meddling and encouraging the turmoil.

Western media accused

Hassan Ghashghavi accused the directors of Voice of America and BBC Persian service of being "officially the spiritual children of [Israeli Prime Minister Benjamin] Netanyahu ... and their aim is to weaken the national solidarity ... and disintegrate Iran."

The BBC and CNN, he charged, had set up a "situation room and a psychological war room."

The BBC's permanent correspondent, Jon Leyne, was forced to leave Iran on Sunday. The Canadian-Iranian correspondent for Newsweek, Maziar Bahari, was also arrested.

Too many votes cast

New details of election irregularities also emerged from analysts who compared official local and provincial results from the recent election with past votes, including the 2005 ballot that brought Ahmadinejad to the presidency.

The numbers simply do not add up, according to Iran expert Ali Ansari in a report for the Chatham House think tank in London.

Two conservative provinces registered more than 100 percent turnout, the report states, while four more topped 90 percent.

Polls prior to the election showed Iran's conservative president was in a tight race, or on his way to defeat. Yet to achieve the official results given him, the report says, in 10 of Iran's 30 provinces, "Ahmadinejad would have needed to win over all new voters, all former Rafsanjani voters, and also up to 44 percent of former reformist voters."